"Xiao Lu, do you have any arrangements for the afternoon? Go to dinner with me!", since going to Professor Nan's house for a year, the relationship between the two has become closer and closer, and even talking has become much closer.

"Oh, who's in for a treat?", what, the United States can also be like this? If it's someone you don't know, won't it seem abrupt if you go by yourself?

"It's Dyson, Witten, Thurston, they're all acquaintances, and this meal is still thanks to you!", Professor Nan laughed, "I made a bet with Dyson that the problem in the seven major mathematical problems would be solved first, he bet on the Yang-Mills equation, I guess it was the Poincaré conjecture, I didn't expect it to be solved by you so quickly!"

Hey, that exam tortured me enough! But Witten and Dyson can have a relationship with each other, although the two of them are also quite accomplished in mathematics, but the relationship with the physics community seems to be closer, and they may have something to trouble them in the future, Lu Qiujian readily agreed, "Okay, I'll go to your office to find you in a while!"

After class, Lu Qiujian threw his things to Alforth and asked him to help send them back to the dormitory, went to buy a bottle of red wine and knocked on the door of Professor Nan's office.

"Hehe, you're quite particular!", Professor Nan saw the red wine in his hand at a glance, took off his coat from the hanger and put it on, "Let's go, it's almost time, let's go over!"

When they arrived at the place, they seemed to be the last to arrive, Freeman Dyson was chatting with Edward Witten and William 0 Thurston when Professor Nan walked over, "What are you talking about?"

"We're talking about birds and frogs!", Thurston beckoned to Luciujian and said as soon as they came to sit down, "Dyson divided mathematicians into two types, one is a bird and the other is a frog, and we are talking about who is the frog and who is the bird!"

This is a bit of Cao Cao's Qingmei cooking wine to talk about the heroes of the world! Professor Nan and Lu Qiujian were both interested, and they were not in a hurry to start eating, so they took a glass of wine and joined their discussion.

Dyson is now about to be 80 years old, he studied mathematics with Hardy of Cambridge University in his early years (well, which one of Ramanuqiang was discovered in the previous article), came to the United States after World War II, worked as Einstein's assistant, and made outstanding contributions to the establishment of quantum electrodynamics, of course, he is best known for the "Dyson sphere" proposed in 60 years.

A "Dyson sphere" is a giant man-made structure envisioned as a "sphere" made up of moons orbiting the sun, completely surrounding the star and receiving most or all of its energy output. Dyson believed that such structures were the logical necessity of civilizations that had been in the universe for a long time and whose energy needs were rising, and he suggested searching for such artificial celestial structures in order to find extraterrestrial supercivilizations.

The "Dyson sphere" also extends a criterion for the rating of cosmic civilizations, and Type I civilizations are able to exploit the natural resources of the world they inhabit. (Humans are currently at level 0.7, not reaching Type I); Type II civilizations should be able to build something like a Dyson sphere and handle the full energy output of their star. Type III civilizations have the technology to harness all the resources of their galaxy, an ability that seems to us to be God's but within the limits of the laws of physics.

Lu Qiujian guessed that 1A7488 may belong to or may exceed the Type III civilization, and if it can complete the Dyson sphere, it can undoubtedly meet the requirements of 1A7488, but this is a bit wishful thinking for human capabilities.

Dyson was old enough and experienced enough to be qualified to judge the living mathematicians, and his eyes turned to Lu Qiujian, and he said slowly, "The bird soars high in the sky, overlooking the vast mathematical vista that stretches to the distant horizon. They like the concepts that unify our minds and bring together many issues from different fields. Frogs live in the mud under the sky and only see the flowers growing around them. They are happy to explore the details of a particular problem, solving only one problem at a time. That's my definition of a bird and a frog, and I'm undoubtedly a frog myself, and Edward is a bird! As for you, you're still young, and the future is still very broad, so it's hard to say for the time being. ”

"Of course, there is no difference between a bird and a frog, and mathematics requires both a bird and a frog. Mathematics is rich and beautiful, as birds give it vast and spectacular vistas, and frogs clarify its intricate details. Mathematics is both a great art and an important science because it blends universal concepts with profound structures. If it is claimed that birds are better than frogs because they see farther away, or frogs are better than birds because they are more profound. ", Dyson continued.

Perhaps feeling that what he said wasn't clear enough, Dyson continued, "Edward and his companions created the string theory, and they flew high in the sky and looked down on the mountains thousands of miles away. In universities around the world, thousands of humble practitioners of string theory are frogs who explore the details of mathematical structures that birds see for the first time on the horizon. Edward, they found a new connection and a new scientific method, so they were birds, and the remaining tens of thousands of string theorists could only work within their framework, so they were frogs!"

Seeing that Professor Lu Qiujian and Professor Nan were as interested in their lectures as Witten and Thurston, Dyson also became enthusiastic**, "These two differences have existed since the birth of modern science, and Bacon and Descartes announced the birth of modern science at the same time, but their views are very different, Bacon said: 'Everything is based on the hard facts of nature as seen by the eye.'" Descartes said, 'I think, therefore I am.' From here it can be seen that Descartes was a bird and Bacon was a frog. ”

According to Bacon, scientists need to travel the globe to gather facts until the accumulated facts reveal how nature moves. From these facts, scientists deduce the laws by which nature works. According to Descartes, scientists only need to stay at home and deduce the laws of nature through pure thinking. In order to derive the correct laws of nature, scientists only need the rules of logic and knowledge of God's existence. ”

"Newton was essentially a Cartesian, and he used the pure thinking of Cartesianism and used this thinking to overthrow the Cartesian dogma of the vortex. Marie Curie was essentially a Baconic school who boiled tons of bituminous uranium slag and overthrew the dogma of the indestructibility of the atom. ”

This divide also extends to the mathematical community, where Hilbert's 23 problems are given to frogs who solve only one problem at a time, and the Bourbaki school, which seeks to unify the entire mathematical framework, is the bird. ”

It seems that there are too many references, and if you are interested, you can go to Baidu Dyson's speech "Birds and Frogs".

12,000 plus more, debt-ridden floating, I will work hard to pay it back!